Electric hot-air heater



O. P. SCOTT.

ELECTRIC HOT AIR HEATER. APPUCAHON FILED SEPT, 1920.

1,389, 1 65 Patented g- 30, 1921.

2 SHEETS-SHUT i.

0. P. SCOTT.

ELECTRIC HOT AIR HEATER.

APPLILZHION FILED SEPT. 1, 1920.

1,389, 165, Patented Aug. 30, 1921.

2 SHEETS-SHEET 2 t/mft alkotvmq PATENT OFFICE.

unaware nor-Ara HEATER.

Specification of Letters Patent.

Patented Aug. 30, 1921.

Application filed September 1, 1920. Serial No. 407,391.

To all whom it may concern:

Be it known that I, Omvnn P. Soon, a citizen of the United States,residin at Tacoma, in the county of Pierce and tate of Washington, haveinvented new and useful Improvements in Electric Hot-Air Heaters, ofwhich the following is a specification.

This invention relates to an electric hot air heater.

The object of the present invention is to provide a simple, practicaland efficient electric hot air heater of strong and durable constructionadapted to be readily installed beneath the floor similar to theradiator of an ordinary hot air furnace and capable of giving a positivecirculation of air through it and of taking cold air from the floor andheating the same and effectively maintaining it at a comfortabletemperature.

A further object of the invention is to provide an electric heater ofthis character in which there will be no loss of moisture or oxygen fromthe ordinary air and over which the heating coil may be operated at arelatively low temperature so that it will not glow and scale or take upmoisture or oxygen from the air passing through the heater.

With these and other objects in view, the invention consists in theconstruction and novel combination of parts hereinafter fully described,illustrated in the accompanying drawings and pointed out in the claimshereto appended, it being understood that various changes in the form,proportion,

size and minor details of construction, within the scope of the appendedclaims, may be resorted to without departing from the spirit of theinvention or sacrificing any of the advantages thereof.

In the accompanying drawings, in which like numerals of referencedesignate correslponding parts in the several figures:

igure 1, is a vertical sectional view of an electric air heaterconstructed in accordance with this invention.

Fig. 2 is a horizontal sectional view of the same.

Fig. 3 is a perspective view of the outer casing and the radiator orgrating. Fig. 4 is a detail perspective view sectional inner core.

Fig. 5 is a similar view of the supporting base. l

In the accompanying drawings in which of the 4 tor or is illustrated thepreferred embodiment of the invention, the electric air heater comprisesin its construction, an outer rectangular casing 1 secured at an opening2 in a floor 3 between two of the supporting joists 4 and composed ofvertical sides and a horizontal bottom 5. The outer casing which may beof any other preferred form or construction is covered at the top by aradiator or grating 6 similar to the radia- %rating of an ordinary hotair furname. he radiator or grating is secured to the floor and theouter casing 1 may be fastened to the radiator or grating 6 in anysuitable manner. Within the outer casing and in spaced relation with thewalls thereof, is an inner wall or casing 7 preferably of cylindricalform but it may of course be of any other desired configuration and itis preferably relatively thick and provided with an interior packing 8of asbestos or other suitable material adapted to prevent heat from thespace inclosed by the inner wall from passing through the latter heatingthe air in the space 9 surrounding the inner wal or casing. The innerwall or casing which is hollow to receive the asbestos packing, may bemade of any suitable material and it is provided at its outer face withan extension or upper section 10 which is relatively thin and whichextends entirely to the grating or register 6 to prevent passage of airacross the top of the inner wall or casing. -The inner Wall or casino;which is open at its top and bottom. is spaced from the bottom 5 topermit the cold air from the floor to pass downward into the space 9 andaround the lower end of the inner wall or casing and upward through thespace 11 inclosed by the said inner wall or casing which containselectrical heating means hereinafter described, whereby the air isheated within the inner wall or casing and is caused to rise and passout of the radiator or grating and produce a positive circulation of airthrough the heater, and room or house.

The heating element comprises a hollow cylindrical col-e12 and a heatingcoil 13. The core which is constructed of fire clay or similarrefractory material is preferably made in two sections 14 to permitexpansion and contraction without cooling stresses and the said core isprovided with an exterior spiral groove 15 in which the wire of theheating coil is sealed to prevent slipping" The wire of the heating coilis designed to be relatively long, viz. 150 ft. and in practice the coilwill he maintained at a relatively low temperature and will not becaused to glow and consume oxygen from the air passing through theheater or eliminate moisture from the air so that the heated airdischarged from the heater will be in its normal moist condition. Theterminals 16 of the resistance coil are connected with teed wires 17which extend through suitable insulators 18 of aluminum or othersuitable material and any number of heating coils may of course beemployed for providing a heating element of the desired power.

The core of the heating element and the inner casing are mounted upon abase 19 of cast metal or other suitable material consisting of acircular central portion or disk 24 and radial arms 21 provided withdepending feet 222 and having lugs 23 and 24 projecting from the upperedges oi the arms and arranged to engage the core and the inner casingintermediate of the same for preventing relative movement of the saidparts of the base. The central circular portion or disk is provided withopenings 25 to permit the air to pass upwardly through the core whichwill become highly heated and which will retain heat for a considerableperiod after the current has been cut off. The outer casing 1 isprovided with an open.- ing 26 formed in one of the Sl(lt walls, whichside wall is equipped with a cover or closure plate 27 adapted tooperate as a damper and also to permit access to the interior ot' theouter casing for cleaning or other purpose. A central vertical rod orbolt 28 extends through the core and is provided at its upper end with ahead 29 and is threaded at the lower end for the reception of a nut 30.The central rod or bolt extends through an aperture 31 of the base andthe head may be engaged with a horizontal bar member 32 extending acrossthe top of the inner casing and arranged upon the upper edge of the samebut the central rod or bolt may engage the radiator or grating or headin any other desired manner as will be readily understood.

\Vhat is claimed iSf 1. An electric air heater of the class describedincluding an outer casing, a radiator or grating extending across thetop of the outer casing, an inner wall or casing arranged within theouter casing in spaced relalion with the walls of thesame and hav ing aportion extending entirely up to the said casing to prevent air frompassing over the top of the inner wall or casing, and a heating elementarranged within the inner wall or casing and adapted to cause a positivecirculation through the heater.

2. An electric air beater oi th o class described including an outerrasing'open at the top, a radiator or grating extending over the top of theouter casing, a hollow inner wall or casing arranged in spaced relationwith the wall of the outer casing and having a non-heat conductingpacking. said inner wall or casing being provided at the top with arelatively thin extension located adjacent the outer face of the saidinner wall or casing and extending entirely up to the grating orregister, a heating element arranged within the inner wall or casing, abase supporting the heating element, and the inner wall or casing, and arod or bolt extending through the heating element and secured to thesaid base.

3. An electric air heater including an outer casing open at the top. aradiator or grating extending across the top of the outer casing, aninner wall or casing arranged within the outer casing and open at thetop and bottom, an electric heating element arranged within the innercasing in spaced relation with the same and comprising a sectional innerhollow core provided with exterior spiral grooves, and a heating coilarranged on the core and seated in the said grooves.

4. An electric hot air heater including an outer casing, open at the topand closed at the bottom for the discharge of heated air, an inner wallor casing arranged in spaced relation with the outer casing andextending to the top of the same, a. heating element having a hollowcore and a base supported upon the bottom of the casing and receivingthe inner casing or wall and the core and having means for engaging andholding the same against relative movement.

5. An electric hot air heater including an outer casing, open at the topand closed at the bottom for the discharge of heated air, an inner wallor casing extending to the top of the outer casing and arranged inspaced relation with the outer casing, a heating element having a hollowcore, and a base receiving the inner casing or wall and the core andhaving means for engaging and holding the same against relativemovement, said base being also provided with legs supported upon thebottom of the outer casing.

6. An electric hot air heater including an outer casing open at the topfor the discharge of heated air having a closed bottom, an inner wall orcasing, a heating element arranged within the inner wall or casing andhaving a hollow core, a. base supporting the inner wall comprising acentral plate or portion, and radial arms having depending feet arrangedupon the bottom of the outer casing, said arms being" lso provided withupwardly projecting gs engaging the core and the inner wall or casingfor holding the same in its relative movement.

7. An electric hot air heater including an outer casing open at the topfor the dis- 1B5 lugs engaging the core and the inner wall or casing forholding the same in its relative movement. and a cylindrical rod or boltsecured at its lower end to the said base.

In testimony whereof I have hereunto affixed my signature.

OLIVER l. SCOTT.

